# A debrief on Quantum Computing by Rahul K, MN

Quantum computing is an exciting new industry popping around the world. Companies like Google and IBM have also been working for quantum computing. As the director of the Washington state Data analytics program, Nella Ludlow says, " Quantum computing promises to be a disruptive technology with such dramatic speed improvements that real tractable solutions to hard problems could be solved in hours and days"(Ludlow 2020). The United States Congress has even approved 1.2 billion dollars of funding towards quantum computing. So what is this exciting new technology and how does it work?

Many people credit Richard Feynman with the concept of quantum computers. In 1981, he gave a lecture in which he stated that a normal computer could not model nature. We could simulate molecules and their reactions so that we could model chemistry or even simulate the Big Bang. Next, a man named Peter Shor came up with the Shor algorithm. This algorithm shows how with a quantum computer we could factorize large numbers much quicker than the algorithms used today. This is very critical because many of our security systems today rely on the fact that it is nearly impossible to factorize a very large number. RSA, which is a common encryption relies on number theory and how it is nearly impossible to factor 2 large primes multiplied together. With a quantum computer and the Shor algorithm, we could break most of these encryptions. A quantum computer using Shor’s law could take a 232 digit number and factor it while it would have taken scientists using hundreds of computers in parallel, two years. Many strides have happened since then and in 2019, Google’s Sycamore device achieved quantum supremacy(which is when a quantum computer solves a problem that would’ve taken conventional computers thousands of years to solve), by solving an equation that would have taken 10,000 years to solve on one of the world’s best supercomputers, IBM’s Summit, by doing it in 3 minutes and 20 seconds.

Quantum computing relies on something called qubits to work. A normal computer works by changing the input for whatever it may be, into 1s and 0s, and then uses an algorithm to solve it and then turns it back into the output. In the circuits of a computer, it would be represented by either a 1 or a 0, so a circuit is open or closed. In the quantum world, it doesn’t have to be so black and white, because electrons and photons can be in 2 places at the same time, which is a key concept of quantum computing called superposition. So a qubit can be 0 and 1 at the same time or even a mixture of 0 and 1. The other key concept in quantum computing is quantum entanglement. Quantum entanglement is when 2 particles are essentially connected so that when you affect something in one particle it does the same in another particle. This means that you can effectively predict the behavior of another particle with just one particle. Even, Albert Einstein referred to quantum entanglement as “spooky action at a distance.” When you entangle more and more qubits together, the calculation ability exponentiates ( if you have one qubit then it is the one qubit raised to the power of another qubit). The only thing about entanglement is that you cannot break the link between the particles. The slightest interference will cause them not to be in the entangled and superpositioned states anymore. This is why most quantum computers are kept near absolute zero (which the point that all particles stop moving).

On the left is Google's quantum computer but on the right is its sycamore processor that actually houses the 53 qubits (Lucero & Stearns, 2019).

Quantum computing is now being used in many applications around the world. One company is called Post-Quantum and is looking to protect people and companies from the cybersecurity risk that is presented by quantum computing. This risk is that by using quantum computers we can crack many of today’s widely used encryption. Another company named ProteinQure is using quantum computing to design protein-based therapeutics. This is made easier by quantum computing’s ability to effectively model particles. The parent company of Mercedes-Benz, Daimler AG is also using quantum computing to manage an autonomous vehicle traffic system. It is also being used in other industries as well, JP Morgan Chase to essentially model and predict the financial market. Microsoft has even gotten into quantum and is using it to change how fertilizer is made. The process was made about a 100 years ago and is very energy consumptive, as it accounts for about 3% of the world’s global energy output and 1% of the contribution towards global warming. They don’t know exactly how the process works and if we figured out how we could save energy significantly by streamlining the process. IBM is using quantum for predicting the weather more accurately because it is a very difficult process. Quantum computing can more accurately use the weather patterns to make the weather forecast more accurate and with that, we can save lives that are lost every year due to natural disasters.

Quantum computing is an immensely useful tool and will be a huge industry in the future. The industry is projected to worth over 64 billion dollars before 2030. With the help of it, we can use it in many different applications from making better medicine to more accurately predicting the weather. Quantum computing will also let us simulate natural events like the Big Bang or even how one chemical reacts to another.

Sources:

__https://news.mit.edu/2016/quantum-computer-end-encryption-schemes-0303__

__https://physics.aps.org/articles/v12/112__

__https://link.springer.com/chapter/10.1007%2F978-3-030-23922-0_2__

__https://www.newscientist.com/article/2220968-its-official-google-has-achieved-quantum-supremacy/__

__https://plus.maths.org/content/how-does-quantum-commuting-work__

__https://www.livescience.com/28550-how-quantum-entanglement-works-infographic.html__

__https://ai.googleblog.com/2019/10/quantum-supremacy-using-programmable.html__

__https://builtin.com/hardware/quantum-computing-applications__